When I sneeze, everyone knows about it. The resulting shock wave rattles windows, wakes sleeping animals, and puts people nearby on edge. My partner, who sneezes like a field mouse with the hiccups, insists I do it on purpose. I maintain that the urge to sneeze at this decibel level is irresistible. Why do some people sneeze so loudly?
What happens when we sneeze?
Let's first establish one thing: sneezing is important for the body. “The nose is an air filter for the lungs,” says Mas Takashimathe chairman of the Department of Otorhinolaryngology and Head and Neck Surgery at Houston Methodist Academic Institute. Inside our noses is a dense network of epithelial cells (a multifunctional cell found throughout the body), tiny hairs, and thick mucus. These elements, Takashima says, “trap particles so that the lungs can be protected.” When those particles build up, they need to be flushed out.
There are also populations of immune cells in our noses, which wake up when they detect high levels of sneeze-causing substances. “Some of the chemicals that are produced as a result of that immune response cause changes in the lining of our nose,” says Sheena Cruickshanka professor in the Department of Immunology at the University of Manchester. Those changes will be familiar to anyone who’s lived through a pollen-laden summer or a mucus-laden winter. The body produces more mucus, swelling starts in the nose, and signals are sent to the brain via the trigeminal nerve, which gives sensation to the face. This signal is processed by an area at the base of our brains called the medulla oblongata, resulting in reflex muscle contractions. It all leads to a sneeze. But while the causes of sneezing vary, there’s no reason why a virus should cause a louder sneeze than grass pollen, says Cruickshank.
What makes some sneezes louder?
Instead, the key to sneeze volume lies in the structure of our respiratory system. The first step of the sneeze reflex, Takashima says, involves deep inspiration.
You need that air to squeeze everything out,” he adds. As air is drawn into our lungs, our vocal cords close tightly. Once enough pressure has built up in our lungs, all the air is squeezed out. “It's that airflow pushing through the vocal cords that creates the sound of the sneeze,” says Takashima. The shape and “flaccidity” of our vocal cords and other soft tissue at the back of the throat influence whether we have a soft or booming sneeze. Lung volume also determines how much air moves in and out of our chest during a sneeze, meaning no physical measurement can predict sneeze volume. “Some people with large lung volumes have very small sneezes,” says Takashima.
The next time I tear apart space-time with a sneeze, can I blame my resonating throat? Unfortunately, Takashima says it's not that simple. “There are societal norms or cultural factors that can influence the sound of a sneeze,” he says.
How to sneeze softly
Takashima points out that in Japan, where there is a heavy cultural emphasis on not bothering others, people manage to suppress their sneezing fits. The key here, he says, is minimizing the amount of resonant energy flowing through your oral cavity – in simple terms, closing your mouth. This, he says, will reduce the volume of your sneeze.
Is the solution to this deafening problem really that simple? A look at the medical literature suggests that sneeze suppression can be a surprisingly bad idea. a case study from a hospital in the Belgian city of Liège is a cautionary tale. During the height of the COVID-19 pandemic — when loud sneezing in public did not go down well — a 38-year-old man reported pain and swelling in his face after holding back a sneeze. A scan showed he had ruptured his sinus. Takashima supports this. “Suppressing sneezing can cause medical problems such as nosebleeds,” he says. “You can force air through the Eustachian tube, which could potentially cause problems with your eardrum.”
But the next time you find a speck of dust stuck in your throat in a library, or while a pet sleeps comfortably nearby, there is an alternative to loud sneezing. “There are times when you don't want to make a scene or you want to try to keep the scene as quiet as possible,” says Takashima. “Keeping your mouth closed while you sneeze can certainly do that.”
